The present invention relates to a surface mounted electronic component mounted on a surface of a printed circuit board in various electronic instruments and having a function, such as an encoder, a variable resistor, or a switch.
Electronic instruments have recently been downsized and thinned, and this requires downsizing and thinning of electronic components used for them strongly. A surface mounted electronic component (it is called electronic component hereinafter) has been preferably used.
The electronic component is mainly a chip type electronic component, but is an electronic component having a function, such as an encoder, a variable resistor, or a switch, which is utilized with an operation knob mounted to an operating shaft.
The electronic component has an output terminal out of a case and a board mounting part, such as a leg, mounted to the case. The board mounting part is soldered to a land of a component-soldered part on the printed circuit board, thereby assuring mounting strength of the electronic component.
A material used for the board mounting part of the electronic component is thinned or narrowed, thereby downsizing and thinning the electronic component and reducing its material.
Such a conventional surface mounted electronic component having a board mounting part will be described hereinafter with reference to the accompanying drawings. FIG. 8 is a front view of the conventional surface mounted electronic component. FIG. 9 is a side view of the component. FIG. 10 is a top view of the component. The surface mounted electronic component 1 includes a resin case 2 and a leg 3 as the board mounting part.
The leg 3 made of metallic flat plate projects outward from a side of the case 2, is bent toward the bottom side of the case 2 at a predetermined position, and extends along a side wall of the case 2. The leg 3 has a soldering part 3A projecting outward from a bottom surface position of the case 2. The soldering part 3A is bent near the case 2 laterally by approximately 90xc2x0. The leg 3 is disposed on each sides of the case 2 opposite to each other of the electronic component 1.
The case 2 accommodates a functioning component, such as an encoder, a variable resistor, or a switch, and the output terminal is guided out of the case 2 (not shown).
A printed circuit board 11 for accepting the electronic component 1 has two lands 12 soldered to the soldering parts 3A of the legs 3, as shown in a perspective view of FIG. 11.
The electronic component 1 is mounted through having the output terminals (not shown) soldered to a predetermined pattern (not shown) on the printed circuit board 11 and through having the soldering parts 3A as the board mounting parts soldered to the lands 12 on the board 11. While being mounted, even if an external force P is applied to the side of the electronic component 1, the electronic component 1 absorbs the external force P with connection between the board mounting parts (the legs 3) and the board 11.
If the conventional surface mounted electronic component 1 having the legs 3 as the board mounting part is downsized and thinned, the leg 3 must be narrowed, shortened, and thinned. This structure accordingly reduces the soldering strength of the soldering part 3A to the board 11 and the strength of the leg 3 itself, so that shortage of the strength against the external force P is concerned.
A surface mounted electronic component includes a case, a leg extending from the case, and a board mounting part at a tip of the leg. The leg includes a projection extending in an extending direction of the leg from the case, and an outer frame formed perpendicularly to the projection away from the case.
The surface mounted electronic component keeps to be mounted tightly to a circuit board even when an external force is applied to the electronic component.